public async Task IoMetricsLive()
{
using (var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync())
{
var receiveBuffer = new ArraySegment <byte>(new byte[1024]);
var receive = webSocket.ReceiveAsync(receiveBuffer, Database.DatabaseShutdown);
using (var ms = new MemoryStream())
using (var collector = new LiveIOStatsCollector(Database))
{
// 1. Send data to webSocket without making UI wait upon opening webSocket
await SendDataOrHeartbeatToWebSocket(receive, webSocket, collector, ms, 100);
// 2. Send data to webSocket when available
while (Database.DatabaseShutdown.IsCancellationRequested == false)
{
if (await SendDataOrHeartbeatToWebSocket(receive, webSocket, collector, ms, 4000) == false)
{
break;
}
}
}
}
}
private async Task <bool> SendDataOrHeartbeatToWebSocket(Task <WebSocketReceiveResult> receive, WebSocket webSocket, LiveIOStatsCollector collector, MemoryStream ms, int timeToWait)
{
if (receive.IsCompleted || webSocket.State != WebSocketState.Open)
{
return(false);
}
// Check queue for new data from server
var tuple = await collector.MetricsQueue.TryDequeueAsync(TimeSpan.FromMilliseconds(timeToWait));
if (tuple.Item1 == false)
{
// No new info, Send heart beat
await webSocket.SendAsync(WebSocketHelper.Heartbeat, WebSocketMessageType.Text, true, Database.DatabaseShutdown);
return(true);
}
// New info, Send data
ms.SetLength(0);
using (ContextPool.AllocateOperationContext(out JsonOperationContext context))
using (var writer = new BlittableJsonTextWriter(context, ms))
{
context.Write(writer, tuple.Item2.ToJson());
}
ms.TryGetBuffer(out ArraySegment <byte> bytes);
await webSocket.SendAsync(bytes, WebSocketMessageType.Text, true, Database.DatabaseShutdown);
return(true);
}